- Locally advanced breast cancer (LABC) (stages IIB, IIIA, IIB as defined by the Union for International Cancer Control and American Joint Committee on Cancer) must be ER positive, HER2 positive or HER2 negative, AND satisfy the following requirements: high endocrine responsiveness (defined as greater than 50% of tumor cells staining for hormone receptors), Grade 1 or 2 histological grade, less than 4 nodes positive, absence of extensive peritumoral vascular invasion, AND pathological tumor size less than 5 cm.